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Deadwood volume

  • Biodiversity

  • Structure

Summary

Standing deadwood volume reflects a broad range of species groups, deadwood specialists and species of conservation concern (Zeller et al. 2022, Gao et al. 2015, Evans et al. 2019, Hekkala et al. 2023, Storch et al. 2023).

Deadwood also indicates stand structural development, accumulating as the forest develops and becomes more structurally complex. Deadwood has functional impacts: contributing to carbon and nutrient cycles, providing a substrate for natural regeneration, and fuelling fires (Ferris and Humphreys 1999).

The rate of the deadwood accumulation in response to management changes depends on forest age. In young forest, the deadwood component will slowly accumulate. However, in mature forest, deadwood volume can increase fairly quickly in response to proactive interventions e.g. after ring-barking or with a reduction in management intensity (Kirby et al. 1998, Agnew and Rao 2014).

Deadwood requires little expertise to recognise and plot-based measurement of deadwood volume is fairly cost and time efficient to conduct (Cosovic et al. 2020).

Methodology summary

The UK National Forest Inventory (NFI) provides a standardised methodology to establish fixed area survey plots and record deadwood volume (Forestry Commission 2020). Standing dead trees, lying deadwood and stumps are recorded.

  • Forest is defined as having >20% canopy cover
  • 0.01 ha plots (5.64m radius) are established, the number of plots is determined by the size of the forest area
  • Within each plot three 10m lying deadwood transects are established
  • The diameter of deadwood is measured wherever it crosses transect line
  • The length, breadth and circumference of each deadwood piece can also be measured to estimate deadwood volume
  • The decay class of each piece of deadwood is also assessed and allocated to one of five categories

The NFI Survey Manual provides the methodology:

  • How to allocate plots – Chapter 12 Plot Assessment
  • How to set up deadwood transects and record deadwood – Chapter 16 Lying Deadwood Transects
  • Recording the decay class of the deadwood – Chapter 18 Decay Classes

A detailed methodology on calculation of standing deadwood volume in m3 per ha is available from the National Forest Inventory team.

Metric threshold or direction of change

The UK National Forest Inventory defines three categories of standing and lying deadwood:
Favourable: >= 80 m3 per ha
Intermediate: >= 20 and < 80 m3 per ha
Unfavourable: 0 – <20 m3 per ha

Taken from: The NFI Woodland Ecological Condition Scoring Methodology.

Technological innovations

Terrestrial laser scanning could be used to estimate deadwood volume in the future (Yrttimaa et al. 2019).

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  • Forest

Scale

  • Community

Cost

  • Low

Tier

  • Tier 2

Technical expertise

  • Low

Standardised methodology

  • Yes